CHAPTER XIII. 

 BRANCH CHORDATA. 



CLASS REPTILIA. 



THERE are four principal forms of reptiles, represented 

 by the lizard, snake, turtle, and alligator. 



THE LIZARDS. 



General Characters of Lizards. Lizards are scaly rep- 

 tiles, having, in the typical forms, two pairs of limbs and 

 an elongated body, with a long, tapering tail, frequently 

 twice as long as the rest of the body. The middle of each 

 vertebra of the tail has a thin layer of cartilage, at which 

 places the tail easily breaks off. The advantage of this 

 arrangement is readily seen. When attacked by an 

 enemy the chances are the lizard will be seized by the 

 tail, for he is probably trying to escape by flight. The 

 brittle tail breaks off, and as this constitutes the greater 

 part of the length, the pursuer thinks he has the main 

 part ; at any rate, while he is holding this the curtailed 

 lizard may make good his escape. But the tail grows out 

 again. 



In capturing lizards, which often lie basking in the sun, 

 it is best to creep stealthily upon them till within arm's 

 length, and quickly dart the hand forward. Unfortunately, 

 in thus grasping them, the tail is in most cases broken off. 



There are five toes, with claws, on each foot. There 

 are no external ears, but the tympanum is sunken, leaving 



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